I'm new to Fluent, and have a very simple, if not silly question that has been bothering me. I have been working through Gambit, and notice that when I want to specify boundary types (with Fluent 5/6 set as the solver), there is no INFLOW boundary type available. An OUTFLOW boundary type is available, along with INTERIOR, INTERNAL, MASS FLOW INLET etc..., but there in no "simple" INFLOW type ? If I change the solver to FLUENT 4, an INFLOW boundary type is available.

Why is there no INFLOW boundary type available for Fluent 5/6, and what should be used in place of it ?? I'm using Gambit 2.0.? and Fluent 5.

Use velocity inlet that is known to you. If it is natural convection type use pressure boundary condition. In forced convection cases you need to specify either mass in or velocity inlet depending on your available data or condition.

In Fluent 5/6, INFLOW boundary is not VALID because neither magnitude nor direction of the flow is specified here, where in the case of OUTFLOW the two values are obtained from calculated flow as specified in the inlet boundaries. So as advised by Ashu use velocity-inlet to define your inlet boundary conditions.